Such intercostals are also referred to as intermediate ribs. They are used to divert forces between ribs, for example door frame ribs and associated secondary ribs.
Intercostals have therefore been installed in the prior art in aircraft structures as a rigid unit, i.e. either in the classic differential design or, for example, as a machined integral component, for example with a continuous shear panel with reinforcing ribs. More recent designs provide for additional regions through which aircraft system lines can be guided, for example electric cables. In such designs construction space and weight are therefore saved.
FIG. 6 illustrates an intercostal 1 known to the applicant, in an elevation. In FIG. 6 it is fastened on the right side to a first rib 11 and on the left side to a second rib 12, wherein it is fitted with an underside by a skin connection 6 on inside I of an outer skin 10 of an aircraft or space craft. Outer skin 10 points with its other side towards outside A, which in FIG. 6 lies at the bottom. Intercostal 1 is fitted to first rib 11 by means of a first connection 4 and to second rib 12 by means of a second connection 5. Second connection 5 is fastened to a front fitting 15 which is reinforced on the other side of second rib 12 by a rear component 14. First rib 11 is, for example, a door frame rib, and second rib 12 is a secondary door frame rib. The intercostals has opening regions 9 which are designed either as bores or open compartments of a framework and through which system lines 23 are guided.
DE 10 2004 009 020 A1 describes an intercostals for aircraft for diverting a load from a first rib to a second rib and/or a skin of the aircraft and has a framework.
One disadvantage here consists in the fact that the enclosed opening regions for the system lines involve “threading” of the lines to be guided through them. In the case of a repair or maintenance the system must first be completely dismantled before the structure can be replaced. In some cases this gives rise to considerable costs, due among other things to the labour and down times of the aircraft.